1. Field of the Invention
The present invention relates to a floppy disk apparatus and, more particularly, to a magnetic head support device for a floppy disk apparatus.
2. Description of the Related Art
A double-sided type floppy disk apparatus comprises two magnetic heads which are supported by a magnetic head support device such that they oppose each other and sandwich a floppy disk therebetween, each magnetic head performing data read/data write in relation to one of the two surfaces (S0 and S1) of the disk.
Unlike a hard disk, a floppy disk may sometimes flex or become locally deformed. Since the magnetic heads come into contact with the disk, this may itself cause the disk to flex. Thus, the magnetic head support device must be able to ensure reliable contact, at all times, between the magnetic heads and the floppy disk, even when the disk is deformed, so as to prevent the occurrence of errors such as off-tracking or off-azimuthing.
With this requirement in mind, a variety of devices have been proposed for the supporting of the magnetic heads of a conventional double-sided floppy disk recording/reproducing apparatus. One such device is disclosed in U.S. Pat. No. 4,291,350, and comprises a pair of magnetic heads which are arranged such that they oppose each other, in a symmetrical arrangement, each of the magnetic heads being supported by a carriage device, through a corresponding gimbal plate which is biased by a compression spring, through a center pivot. The magnetic heads mounted on the gimbal plates are pivotal about the axis (x-axis) extending in the access direction of the magnetic heads, and are also pivotal about the axis perpendicular to the x-axis, i.e., an axis (y-axis) extending along the tangential direction of disk rotation. In addition, the magnetic heads are movable along the axis (z-axis) perpendicular to the floppy disk surface. In this device, a pair of magnetic heads reliably follow local displacement of a disk. However, the loading positions of the magnetic heads are indefinite, and unloading postures of the magnetic heads are unstable, resulting in difficult adjustment. Particularly, in a recent and advanced floppy disk apparatus having a high track density and a high linear recording density, when the magnetic heads are inclined at a large angle, off-tracking or off-azimuthing may occur. U.S. Pat. No. 4,151,573 (Tandon et al.) discloses another type of magnetic head support device. In this device, an S0-side magnetic head is fixed, and an S1-side magnetic head is pivotal about the x- and y-axes and movable along the z-axis. A floppy disk is urged by the S1-side magnetic head toward the S0-side magnetic head, thereby suppressing displacement of the floppy disk. This device has good contact properties of the magnetic heads with the disk, and off-tracking rarely occurs. However, the magnetic head must be strongly urged against the disk, and the service life of the magnetic heads and the disk may be shortened due to wear.